Metallic arc-welding apparatus



Dec. 27, 1927. v 1,654,382

v F. C. OWEN METALLIC ARC WELDING APPARATUS Filed Feb. 12, 1925 F C. Owen Patented Dec. 27, 1927.

UNITED STATES PATENT OFFICE.

. METALLIC ARC-VIELDING APPARATUS.

Application filed February This invention relates to traiisformers, and more particularly to transformers especially designedfor use in connection with electric arc welding apparatus.

The'invention has for one of its objects the provision of a transformer of the character statedwhich will reduce to the minimum the rise and fall of the amperage delivered to the electrode of an arc welding 0 apparatus and which will prevent fluctuations in the How of current to the electrode,

with the result that an are which is uniform and will not burn the metal being welded may be easily maintained. A-,fu1*t11er object of the invention is the provision of a transformer of the character stated which will efiiciently function Without damping devices, rhepsta-ts, resistances of all kinds and similar devices now employed in connection with arc welding apparatus, whereby to reduce to the minimum the cost of manufacturing and the operating expense of arc welding appartus.

WVith the above and otherobjects in View,

-. the invention consists of the combination and arrangement of parts hereinafter fully described and claimed, and illustrated in the accompanying drawing, wherein:

The figure is a diagrammatic view ofan :50 arc welding apparatus embodying my improved transformer. r

' As shown in the drawing, the transformer comprises a laminated core 1 which is preferably of oblong formation. The primary circuit of the transformer comprises sections or coils 2, 3 and 4 arranged in series on three adjacent legs of the core. The coils 2 and 4 are mounted on the short limbs, and coil '3 on one of the long limbs of the core 1. The

coils 2 and 4 preferably have a similar number of turns or convolutions and may be termed auxiiiaryeoils, and the coil 3 has a greater number of turns or convolutions than one of the other coils and may be termed the primary coil.- Leads 6 and 7 extend from the coils 2 and 4 to a switch 5,

and leads 8 and 9 extend from any suitable source of current supply to the switch.

The secondary circuit of the transformer comprises amain-section or coil 10 which is mounted on the long limb of the core 1 that carries the primary coil 3, and an auxiliary section or coil '11 mounted on the other long limb of the core. The coils '10 and 11 are reversely wound or reversely connected, and are connected in series by a wire 12 so 12, 1925. Serial No. 8,790.

that their voltages are added; The coil 11 has a greater number of turns or convolutions than the coil 10, and extending from certain turns or convolutions thereof are from the coil 10 to the contact jaw 20 of a switch 21 the blade 22 of which is grounded,

and a lead 23 extends from the wire 12 to the other contact jaw 24 of this switch. A

lead 25 extends from one ,of the convolutions of the coil 10 to the contact'jaw 26 of the switch 14. The table 27 of the are welding apparatus is, as shown in the drawing, grounded.

The switch 21 permits either end of the coil 10 or one end of coil 11 and one end of coil 10 to be groundedl lVhen the blade 22 of this switch 'isin contact with jaw 20 and the blade 15 of the switch 14 is in contact with one of the jaws 13, a secondary circuit is established whiclrincludes the coil 10, certain of the turns or convolutions of the coil 11 and, the electrode 17. When the blade 22 is in contact with jaw 24, and the blade '15 in contact with one of the jaws 13, a secondary circuit is established, which includes certain of theturns or convolutions of the coil 11 and the electrode 17, and automatically cuts out coil 10. YVhen it is desired to weld a small article, the blade 22 is swung in contact with jaw 24, and the blade 15 in contact with one of the jaws 13. \Vh'e'n it is desired to weld a medium or heavy article the blade 22 is swung in contact with jaw 20, and the blade 15 into contact with jaws marked 13, while when it is desired to fill the scores of an engine cylinder withmetal, the j blade 22 is swung in contactwith jaw 20 and the blade 15'into contact with jaw 26, which automatically cuts out coil ,11 and a current of three to four hundred ampercs flows to score filler rod when contact ismade with cylinder.

Current flowing through the coils 2, 3 and 4, constituting the primary winding, tends to cause a magnetic flux to circulate through the four legs of the core 1. Practically all the flux developed by this primary winding will thread the main secondary winding section or coil 10, because of the close association of this secondary coil with the primary,

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and flux in this part oi the core remains substantially'const-ant at all loads.- As a result, the voltage generated in this secondary coil 10 likewise remains practically the same at all times, and does not vary with the load.

The auxiliary section or coil 11 of the secondary windinp', however, being remote from the primary winding, tends to set up a flux independent of and opposed to that gen,

erated by the primary winding. Owing to the location of the coils, this sccondaryfiux is confined substantially to that leg of the core on which'the coil 11 is mounted. The primary flux threads the other three legs of the core, and also tends to permeate the fourth leg. In this fourth leg, however, it is opposed and choked back by the flux due to the secondary winding 11. By reason of the shape of the core and position of the separated primary windings on three legs thereof, there will be a certain amount of flux leakage from each end of the primary coils 2 and 4c. Owing to the opposing; and choking effect of the secondary coil 11, however, a very exaggerated leakage takes place at the two lower corners of the core, or, in other words, by far the greatest proportion of flux is forced out of the closed metallic path into the air at these points. The larger thecur rent drawn from the secondary winding, the greater this leakage becomes.

As a result of such leakage, the heavy secondary flux causes the coil 11 to develop high inductance, and'act as an impedance coil, that the phase of the voltage in this part of the secondary winding is shifted. The resultant voltage at the are is therefore ,re duced, or at least prevented from increasing, as the current increases. The impedance action increases with the load, so that, even on short circuit, it serves to prevent an excessive or dangerous flow of current. Thus a stable are is maintained.

These transformers are to be built to opcrate on either single or three phase alternating current, and are to be inclosed in either wood, cast iron, steel or aluminum cases, and are to be oil insulated and cooled, or air cooled.

From the foregoing description, taken in connection with the accompanying drawing, it should be understood that I have provided a transformer which will deliver the desired amperage to the electrode 17. The apparatus is highly eiiicient and does not require the use of damping devices, rheostats, resistances and similar devices, and will enable an are which will be uniform and will not burn the metal being welded to be easily maintained.

Vhat is claimed is z- 1. Apparatus for metalicare welding'conv prising a transformer having a closed circuit rectangular core, a primary winding, embodying a main section and auxiliary sections mounted on three adjacent legs of the core, said main section having,- a fII'GiltGI number of turns or convolutions than each of the auxiliary sections, and a secondary winding -en'1boc'lyin;r a main section wound on the middle one of said three legs and an auxiliary section mounted on the opposite leg of the core.

2. Apparatus for metallic arc welding eon'u'irisinp; a transformer having a rectangular core. a primary winding distributed on three adjacent legs of the core, a secondary Winding embodying; a main section on the middle one of said three legs and an auX- iliary section on the opposite or fourth leg of the core, an electrode connected to the auxiliary section, a wire connecting the adjacent ends of said sections, ground leads ex tending from the opposite end of said main section and from said wire, and a switch by means of which either of said leads may be grounded.

In testimony whereof I ailix my signature.

FREDERICK C. OWEN. 

